Bevel gears, such as hypoid gears having curved teeth, are cut using a disk shaped tool head that comprises a plurality of blades (for example, refer to patent documents 1, 2 and 3). This kind of tool head is used by attaching the tool head to a tooth cutter, and by controlling the tool head and the work such that they have a specified positional relationship, it is possible to cut concave tooth surfaces or convex tooth surfaces having a specified shape into the work.